1) Field of the Invention
The present invention relates to a curing agent for epoxy resins comprising a reaction product of diamine and a diglycidyl compound, an epoxy resin composition comprising said curing agent for epoxy resins and an epoxy resin cured product obtained by curing said epoxy resin composition.
2) Related Art
It has been well known that various polyamine compounds are widely used as a curing agent for epoxy resins and a raw material thereof. The room-temperature curable epoxy resin compositions using these curing agents for epoxy resins are particularly utilized widely in a field of coating materials such as a corrosion-resistant paint for ships, bridges and land and marine iron structures and a field of civil engineering and construction such as materials for lining, reinforcement or repair of concrete structures, flooring materials of buildings, linings of water supply and sewerage systems, pavement materials, and adhesive materials.
Among these polyamine compounds, a curing agent for epoxy resin using isophoronediamine as a raw material has features such that it provides a coating film excellent in both gloss and leveling and a cured product excellent in both water resistance and chemical resistance compared with a curing agent for epoxy resin containing an aliphatic polyamino compound or a curing agent for epoxy resin using an aliphatic polyamino compound as a raw material. (See “New Development Of A Curing Agent For Epoxy Resins” edited by Hiroshi Kakiuchi, published by CMC Co. Ltd., P 41-49, May 31, 1994)
However, since a curing agent for epoxy resins using isophoronediamine as a raw material has low reactivity with epoxy resins at low temperature, it has such problems that it takes long time to cure or it is difficult to obtain intended performances because the curing reaction does not proceed sufficiently.